This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The small GTPase RhoA is a critical switch protein for cytokinesis. In a recent set of experiments, we found that ectopically expressed (and endogenous, to a lesser extent) RhoA is covalently modified and migrates with about a 4kd shift to a slower mobility form on a SDS gel. RhoA is a target for additional modifications and many of these have provided significant insight. We propose to characterize this modification by mass spectrometry.